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UNITED STATES PATENT OFFICE.

\VILLIE F. LOCKE, OF CONCORD, NEIV HAMPSHIRE, ASSIGNOR OF ONE HALF TO JOHN E. ROBERTSON, OF SAME PLACE.

INSULATOR.

SPECIFICATION forming part of Letters Patent No. 360,354, dated March 29, 1887.

Application filed October 1, 1886.

To all whom it may coir/earn.-

Be it known that I, WILLIE F. LooKE, a

citizei'i of the United States, residing at Concord, in the county of Merrimac and State of New Hampshire, have invented certain new and useful Improvements in Insulators; and I do hereby declare that the following is a full and exact description thereof, reference being had to the accompanying drawings, making part of this specification.

The object of this invention is to provide an improved method of insulating the linewires of telephone and telegraphic circuits, and is especially adapted for use in connection with the line -wires of acoustic or mechanical telephones; and the invention consists in the general and specific features of construction and arrangement hereinafterset forth and claimed.

The invention is illustrated in the accompanying drawings, in which Figure 1 represents a central longitudinal section of the insulator, and Fig. 2 is a crosssection thereof.

Like letters designate corresponding parts in both the figures.

The essential feature in the construction of my improved insulator is a central air-chamber surrounded by non conducting material, by means of which foreign sounds are prevented from being conveyed to the wire from the support of the insulator.

To this end the insulator is constructed and arranged in the following manner: An airchamber, A, is formed by means of a cylindrical tube, B, of any suitable substancewood or metal-and. two caps, O 0, one at each end of the tube.

These caps may be, as shown, conicatshapedplngs of wood or other semi-elastic substance, fitting tightly against and within the ends of the tube, or they may be formed of metal and soldered or otherwise attached to the tube. Through the middle of each of these caps C C, and thus passing through the center of the tube 13 longitudinally, is the supporting screw or bolt D, by means of which the insulator is fastened to the pole or other support. Around the outer surface of the tube B, inclosing the air-chamber, is a tube of non-conducting material, E- such as rubber-and against this insulating material the line-wire is fastened by any convenient method of attachment.

The air-chamber A, formed around the sup- Serial No. 215,079. (No model.)

porting-rod D and within the tube B, outside of which the line-wire is attached, prevents vibrations caused by any outside influence, as the wind, from being conveyed from the linewire pole or support to the wire itself, and for this reason is of especial use in connec tion with the circuit-wires of acoustic or mechanical telephones, where every foreign vibration tends to confuse the vibrations which are to be transmitted from one end of the line to the other.

When conical caps or plugs C C are used,they are held tightly and firmly in position, either by means of the supporting-screw, by means of which they are drawn toward each other, or, in case a bolt is used, they may be retained by means of anut having a screw-thread which fits upon a corresponding screw-thread cut in the bolt.

Instead of having two tubes, as herein de scribed, one of metal and the other of rubber, a single tube of hard rubber or other suitable substance may be used, provided it is made of sufficient strength to withstand the strain of the wires.

I claim as my invention- 1. In an insulator for telephone and-other wires, the cylindrical inner tube, B, and caps C C, one at each end of the tube, inclosing air-chamber A, outer tube, E, of non-conducting material, and supporting screw or bolt D, passing through the center of the caps C C, substantially as and for the purpose herein specified, whereby the supporting screw or bolt is surrounded by the air-chamber.

2. In an insulator for telephone and other wires, the combination of the inner tube, B, outer tube, E, of nonconducting material, and conical caps C C, fitting into and against the ends of the said inner tube and held in position by the supporting screw or bolt D, substantially as and for the purpose herein specified.

3. A11 insulator for telephone and other wires, consisting of a closed tube of non-conducting material, as rubber, surrounding an air-chamber through which passes the supporting bolt or screw D, as and for the purpose herein specified.

\VILLIE F. LOCKE.

LJI 

